Chemically resistant cotton materials



Jan. 17, 1956 G. L. DENISTON 2,731,369

CHEMICAL-LY RESISTANT COTTON MATERIALS Original Filed Aug. 14, 1951 INVENTOR GEORGE L. DEW/8T0 PM i WM ATTORNEYS 2,731,369 rates-tea Jan; 1?, 956

mists p CHEMICALLY RESISTANT corronitvmrnnrars l monwealth E ne d e Cgmpa y o Oh ,Ohio, acorporationofltio 1 l H Original application-August 14, 1951, Serial No. 241,75),

now Patent No. 2,706,690, dated April 19, 1955. Di-

Dayton,

ivided: andthis'application iMay d, 1954', .No.

" T Siuveutionrelates to; process, ottreating cotton threads, yarns and fabrics with dextranand its derivatives and to the products produced thereby.

Dextran is a water soluble colloidal material produced by the action of microorganismson sucrose bearing materials and may" be converted into" dextran ethers and esters as described in U. S. Patents,2,3,44,l79;2,203;7.02

and2,385,553. i

This invention contemplates the. provision of a novel process for the impregnation and coating of cotton materials with dextran and its derivatives.

The invention contemplates the provision of a new product wherein cotton provides a strength core and material impregnated therein and coated thereon provides an outer shell resistant to ordinary chemical attack but which may be rendered sufficiently tacky by selected solvents for the securing of good adhesions in many materials of commerce.

More particularly, in the process of invention cotton in the form of a thread, yarn or fabric is treated with dextran, dissolved in a solvent, to secure penetration of the dextran into the fibers, and thereafter the dextran bearing cotton is treated with an alkylating agent in an alkaline solution and then subjected to a heating step to form a product resistant to chemical action but selectively attacked by particular solvents. An additional feature of the process, particularly as related to commercial yarn and fabrics as used in rubber and plastic industries, is the substantial elimination of residual stretch therefrom by the heating of the composite body under tensive conditions. While I prefer to use a combination of sodium hydroxide and water as the dextran solvent, due to the efficiency of this combination in the effecting of a swelling of the cotton fibers to thereby permit maximum penetration of the dextran, other solvents, e. g. water alone, water and sodium carbonate, a dilute acetic acid solution or dilute solutions of the mineral acids such as HCl and H2804 may suitably be employed.

The alkylating agent for the dextran, which is utilized to substitute or add an alkyl group into the dextran, may include: the organic halides such as methyl, ethyl, propyl, isopropyl or benzyl halides; the alkyl sulphates such as diethyl sulphate; tri-ethyl phosphate; and aryl sulfonic alkyl esters such as the ethyl ester of p-toluene sulfonic acid.

The alkylating agent is employed in alkaline solution and this alkali is preferably sodium or potassium hydroxide, sodium carbonate or an organic alkali.

The product of the process of invention may comprise, for example, a destretched yarn having the cotton core surrounded by the benzyl ether of dextran which is insoluble in and substantially unaffected by H2O, alkalis, mineral acids, and the lower aliphatic alcohols, but which when treated with acetone, dioxaue, benzene or toluene becomes tacky. Thus this destretched yarn has a particular utility in power transmission belt structures where ,it may be laminated with rubber and cured thereto. Similarly a fabric treated by the process of invention attains qualities suitable for lamination with resinous materials.

The invention will ,be rnore, fully understood by reference to the following specific examples and the drawing wherein: e

Figure l of invention;

t Figure} is aview of the grooved roller in Figure l; Figure 3 is a partial plan view of the apparatus. of Figure 1;aud ,,,,Figure .4 is a plan view of the grooved tapered roller shown in the oven of Figure 1.

illustrates the apparatus used in the process Example I There is shown in Figure 1 a tank or vat 1 containing a? aenran solution 2, the solution containing by weight approximately 40% dextran of any molecular weight, 55% water and about 5% of sodium hydroxide. A cotton yarn 3 is shown passing continuously from bobbin 4, mounted on roll 5, into the solution 2 where it is guided between rolls 6 and 7, which are adapted to be driven independently by means not shown at speeds differing by about 30%, the roll 7 having the greater velocity. The rolls 6 and 7 are multi-grooved as shown in Figure 2 in order that the time of passage of the yarn through the solution may be readily controlled, by utilization of a selected number of grooves for particular size yarns.

The yarn is shown in Figure l as passing from solution 2 over roll 8 into bath 9 containing alkaline alkyl halide solution 10 having by weight approximately 30% of benzyl chloride, 9% of sodium hydroxide and 61% water. The wetted and impregnated yarn 3 passes over rolls 20 and 21 which are grooved similarly to rolls 6 and 7 and after a multi pass through the solution, as more clearly seen in Figure 3, enters a heated oven 12 over roller 11. A hollow conical die 13 is positioned between bath 9 and oven 12 to remove any excess material present on the yarn before it passes to the heating operation.

The oven 12 is provided withgrooved rollers 14, 15, roller 15 being driven at a speed about 30% in excess of that of roller 14, and the roller 15 having grooves of progressively (Figure 4) increasing diameter, from end 16 to end 17, to facilitate the destretching of the yarn. After curing the yarn is wound up on coil 18 mounted on stand 19.

When impregnating and coating the yarn is passed through bath 3 under tension if desired although the same is not necessary but does assist in the ultimate de-stretching of the yarn and the dextran pick up is somewhat greater if tension is employed. In solution 10 the dextran and aralkyl halide initiate a reaction which is completed in oven heater 12 at temperatures of about to C.

The finished product has substantially no stretch retained therein and due to the coating resists moisture thus preventing shrinkage effects from occurring in the yarn rendering the product particularly useful where constant yarn length under varying humidity conditions is essential. Since the product is also resistant to alcohols, the mineral acids, and alkalis, it may be employed under conditions where such resistance is beneficial.

It will be clear from the foregoing that the degree of impregnation of the yarn may be controlled by controlling the solution concentrations particularly the dextran. Furthermore a coating may be applied over the yarn to completely sheath the same by utilizing viscous solution.

Example II The apparatus described in connection with Example I may be readily modified to permit the coating of a cotton fabric with an ethyl dextran which is resistant to water, the mineral acids, and alkalis, but soluble in the alcohols.

Ihe dextran may in thisin stance be. solved inl atweak sodium hydroxide, 'and -an eflicient mixture would contain:

50% dextran 5Q% ater %:qdi m.-hv roxide "The fix-ing solution may contain:

50% di-ethyl sulphate 3. ;W r' 20% sodium hydroxide The procedure'is essentially thesame as setforth in Example L 'the heating temperature however. being of the order of IOU-115 C.

P edu@ ihe n i me isio vls bi ze rine benzyl== fih and potentially tacky by treatment with an organic solvent-for the-benzyl-ether. Y

2. A cotton yarn impregnated and coated with, and stabilized in essentially non-stretchable condition by, a benzyl ether of dextran formed in and on the yarn while the latter is in swollen condition, the impregnated cotton yarn being potentiallytacky. by treatment with an organic solvent for the benzyl ether.

' :-3 A cotton-thread sheathed in awateninsoluble benzyl ether of dex'tran formed in-arid ;on the thread while the latter is in swollen condition; the'sheathedcotton thread being ctq a y tact v by tre tment ,w th a or a solventrf the benzvl ethe a :4. iA-m0iStUlTQ 15EOOf cotton yarn for power transmission belting comprising a cotton core impregnated-and coated with, and. stabiliz ed no mstretchable condition by, a Waterinsolub1e benzyl'ether of dextran formed in and on the yarn while the latter is in swollen condition,

the impregnated cott'on 'yarn being potentially "tacky by treatment; with an origa nic --sollven't for the" bengyl ether.

" Q Refere i ji tlt tfil 19 t i l m UNITED STATES PATENTS ='Goldthwait July 4,1944 2,372,601 Nickerson Mar. 27,1945 2,503,624 "I uaces Apr. 11, 1950 "ra r- 

1. A COTTON PRODUCT IMPREGNATED AND COATED WITH A BENZYL ETHER OF DEXTRAN FORMED IN AND ON THE PRODUCT WHILE THE COTTON IS IN SWOLLEN CONDITION, THE IMPREGNATED PRODUCT BEING DIMENSIONALLY STABILIZED BY THE BENZYL ETHER AND POTENTIALLY TACKY BY TREATMENT WITH AN ORGANIC SOLVENT FOR THE BENZYL ETHER. 